JP2020086125A - Polarization plate set - Google Patents

Abstract

To provide a polarization plate set suppressing a warp under a high-temperature and high-humidity environment of a liquid crystal panel.SOLUTION: A polarization plate set includes: a first polarization plate 21 being 200-300 μm thick arranged on one side of a liquid crystal cell 10; and a second polarization plate 22 being 150 μm thick or less and arranged on the other side of the liquid crystal cell 10. The first polarization plate 21 includes: a retardation layer 32 being 100 μm thick or more; a polarizer 31 being 10 μm thick or less arranged on one side of the retardation layer 32; and an adhesive layer 33 arranged on the other side of the retardation layer 32. The first polarization plate 21 is laminated onto the liquid crystal cell 10 interposing the adhesive layer 33.SELECTED DRAWING: Figure 1

Description

The present invention relates to a set of polarizing plates.

An image display device (for example, a liquid crystal display device) typically uses a display panel in which polarizing plates are arranged on both sides of a display cell. The configuration of each polarizing plate differs depending on the desired characteristics. Therefore, polarizing plates having different thicknesses may be arranged on both sides of the display cell. When polarizing plates having different thicknesses are arranged, the contracting stress of each polarizing plate is different, so that the liquid crystal panel may warp in a high temperature and high humidity environment. As a result, problems such as light leakage and display unevenness occur in an image display device provided with these polarizing plates. As a means for suppressing the warp of a liquid crystal panel in a high temperature and high humidity environment, a method of laminating a protective film having a specific tensile elastic modulus on a polarizing plate having a concave shape has been proposed (for example, Patent Document 1). .. However, the technique relates to a thin polarizer, and there is a problem that a warp cannot be sufficiently suppressed by a polarizing plate having a constituent element having a certain thickness (for example, a retardation layer) and a large polarizing plate. is there. Therefore, even for a polarizing plate including thick components and a large polarizing plate, a set of polarizing plates capable of suppressing the warpage of the liquid crystal panel in a high temperature and high humidity environment is required.

Japanese Unexamined Patent Publication No. 2018-72533

The present invention has been made to solve the above problems, and a main object thereof is to provide a set of polarizing plates capable of suppressing the warpage of a liquid crystal panel under a high temperature and high humidity environment.

The polarizing plate set of the present invention comprises a first polarizing plate having a thickness of 200 μm or more and 300 μm or less arranged on one surface of a liquid crystal cell, and a thickness of 150 μm or less arranged on the other surface of the liquid crystal cell. It is composed of a second polarizing plate. This first polarizing plate comprises a retardation layer having a thickness of 100 μm or more, a polarizer having a thickness of 10 μm or less arranged on one surface of the retardation layer, and an adhesive agent arranged on the other surface of the retardation layer. And layers. The first polarizing plate is laminated on the liquid crystal cell via the adhesive layer.
In one embodiment, the first polarizing plate further has a protective layer, and the protective layer is laminated only on one surface of the polarizer.
In one embodiment, the creep value of the pressure-sensitive adhesive layer is 80 μm/h or more.
In one embodiment, the pressure-sensitive adhesive layer has a thickness of 10 μm to 40 μm.
In one embodiment, the first polarizing plate is arranged on the back side and the second polarizing plate is arranged on the viewing side.
In another aspect of the present invention, a liquid crystal panel is provided. This liquid crystal panel includes the above-mentioned set of polarizing plates and a liquid crystal cell.
In one embodiment, the distance between the liquid crystal cell and the polarizer of the first polarizing plate is 120 μm to 190 μm.

According to the present invention, there is provided a set of polarizing plates capable of suppressing warpage of a liquid crystal panel under a high temperature and high humidity environment. The polarizing plate set of the present invention comprises a first polarizing plate having a thickness of 200 μm or more and 300 μm or less arranged on one surface of a liquid crystal cell, and a thickness of 150 μm or less arranged on the other surface of the liquid crystal cell. And a second polarizing plate. The first polarizing plate comprises a retardation layer having a thickness of 100 μm or more, a polarizer having a thickness of 10 μm or less arranged on one surface of the retardation layer, and a pressure-sensitive adhesive arranged on the other surface of the retardation layer. A layer, and the first polarizing plate is laminated on the liquid crystal cell via the pressure-sensitive adhesive layer. By having such a configuration, it is possible to suppress warpage of the liquid crystal panel under a high temperature and high humidity environment, and as a result, prevent light leakage and display unevenness in the liquid crystal display device. Further, the retardation layer included in the first polarizing plate used in the present invention has a thickness of 100 μm or more. Therefore, even if a slight warp occurs in the liquid crystal panel under a high temperature and high humidity environment, the influence of the warp on the optical characteristics of the retardation layer can be suppressed. As a result, the desired optical characteristics of the retardation layer are maintained well, and it is possible to prevent the display characteristics of the liquid crystal display device from deteriorating even when placed in a high temperature and high humidity environment.

1 is a schematic cross-sectional view of a liquid crystal panel including a set of polarizing plates according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
The definitions of terms and symbols in the present specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), and “ny” is the direction in the plane that is orthogonal to the slow axis (that is, the fast axis direction). , And “nz” is the refractive index in the thickness direction.
The “refractive index” of a film that causes birefringence after stretching refers to a value calculated by (nx+ny+nz)/3, unless otherwise specified.
(2) In-plane retardation (Re)
“Re(550)” is the in-plane retardation of the film measured with light having a wavelength of 550 nm at 23° C. Re(550) is calculated|required by Formula:Re=(nx-ny)*d, when the film thickness is d (nm). Note that “Re(450)” is the in-plane retardation of the film measured with light having a wavelength of 450 nm at 23° C.
(3) Phase difference (Rth) in the thickness direction
“Rth(550)” is the retardation in the thickness direction of the film measured with light having a wavelength of 550 nm at 23° C. Rth(550) is calculated|required by Formula:Rth=(nx-nz)*d, when the film thickness is d (nm). In addition, "Rth(450)" is a retardation in the thickness direction of the film measured with light having a wavelength of 450 nm at 23°C.
(4) Nz coefficient The Nz coefficient is calculated by Nz=Rth/Re.

A. Overall Configuration of Polarizing Plate Set FIG. 1 is a schematic cross-sectional view of a liquid crystal panel including a polarizing plate set according to an embodiment of the present invention. In the liquid crystal panel 100, a first polarizing plate 21 and a second polarizing plate 22 are laminated on both sides of the liquid crystal cell 10. The thickness of the first polarizing plate is 200 μm or more and 300 μm or less, and the thickness of the second polarizing plate is 150 μm or less. In the illustrated example, the first polarizing plate 21 includes a retardation layer 32 having a thickness of 100 μm or more, a polarizer 31 having a thickness of 10 μm or less arranged on one surface of the retardation layer 32, and a retardation layer of the retardation layer 32. It has a pressure-sensitive adhesive layer 33 arranged on the other surface, and a protective layer 34 if necessary. The first polarizing plate 21 is laminated on the liquid crystal cell 10 via the adhesive layer 33. The second polarizing plate 22 has a polarizer 35, a protective layer 37 arranged on one surface of the polarizer 35, and an adhesive layer 36 arranged on the other surface of the polarizer 35. .. The second polarizing plate 22 is laminated on the liquid crystal cell 10 via the adhesive layer 36. The polarizer 31 and the protective layer 34, and the polarizer 35 and the protective layer 37 may be laminated via any appropriate adhesive layer (not shown). Further, the first polarizing plate 21 and the second polarizing plate 22 may further include any appropriate other layer (not shown). Other layers include surface treatment layers and other protective layers. In the set of polarizing plates of the present invention, typically, the first polarizing plate is arranged on the back side and the second polarizing plate is arranged on the viewing side.

The first polarizing plate 21 has a thickness of 200 μm or more and 300 μm or less. The retardation layer 32 of the first polarizing plate 21 has a thickness of 100 μm or more. The thickness of the polarizer 31 of the first polarizing plate 21 (hereinafter, also referred to as the first polarizer) is 10 μm or less. In one embodiment, the first polarizing plate 21 preferably further has a protective layer 34. In this embodiment, it is preferable that the polarizer 31 of the first polarizing plate 21 has a protective layer on only one surface. With such a configuration, it is possible to prevent the thickness of the first polarizing plate 21 (more specifically, the distance from the first polarizer to the liquid crystal cell) from becoming too thick, and to prevent the thickness from increasing in a high temperature and high humidity environment. The warp of the liquid crystal panel can be suppressed.

In one embodiment, the distance between the polarizer 31 of the first polarizing plate and the liquid crystal cell 10 is preferably 120 μm to 190 μm, more preferably 140 μm to 190 μm, and further preferably 160 μm to 190 μm. When the distance between the polarizer 31 and the liquid crystal cell 10 is in the above range, warpage of the liquid crystal panel under a high temperature and high humidity environment can be suppressed. In the present specification, the distance between the polarizer and the liquid crystal cell refers to the distance from the center of the polarizer (half the thickness of the polarizer) to the portion in contact with the liquid crystal cell. Specifically, in FIG. 1, it means a value obtained by summing the value of 1/2 of the thickness of the polarizer 31, the thickness of the retardation layer 32, and the thickness of the pressure-sensitive adhesive layer 33.

The second polarizing plate 22 has a thickness of 150 μm or less. The second polarizing plate 22 may have a thickness of 150 μm or less, and may include any appropriate layer. The second polarizing plate 22 includes, for example, a polarizer 35, an adhesive layer 36 arranged on one surface of the polarizer 35, and a protective layer 37 arranged on the other surface of the polarizer 35. Including. In this embodiment, the total thickness of the polarizer 35, the pressure-sensitive adhesive layer 36, and the protective layer 37 may be 150 μm or less.

In one embodiment, the distance between the polarizer 35 of the second polarizing plate and the liquid crystal cell 10 is preferably 50 μm to 90 μm, more preferably 50 μm to 70 μm, and further preferably 55 μm to 65 μm. If the distance between the polarizer 35 of the second polarizing plate and the liquid crystal cell 10 is in the above range, warpage of the liquid crystal panel under a high temperature and high humidity environment can be further suppressed.

B. First Polarizing Plate As described above, the first polarizing plate 21 has a thickness of 200 μm or more and 300 μm or less, preferably 200 μm to 280 μm, and more preferably 220 μm to 250 μm. The first polarizing plate 21 includes a retardation layer 32 having a thickness of 100 μm or more, a polarizer 31 having a thickness of 10 μm or less arranged on one surface of the retardation layer 32, and the other surface of the retardation layer 32. It has the adhesive layer 33 arrange|positioned. The first polarizing plate 21 is attached to the liquid crystal cell via the adhesive layer 33. As described above, the thickness of the first polarizing plate is thicker than that of the second polarizing plate. In the set of polarizing plates of the present invention, the distance from the center of the polarizer of the first polarizing plate to the liquid crystal cell (specifically, half the thickness of the polarizer, the thickness of the retardation layer, and the pressure-sensitive adhesive layer). The sum of the thickness and the thickness of) does not become too thick. With such a configuration, warpage of the liquid crystal panel under a high temperature and high humidity environment can be suppressed.

In one embodiment, the first polarizing plate 21 preferably further has a protective layer 34. By having a protective layer, a polarizer can be protected appropriately. The protective layer 34 is preferably laminated only on one surface of the polarizer. Since the protective layer is laminated on one surface of the polarizer, more preferably on the surface of the polarizer 31 on which the retardation layer 32 is not laminated, the polarizer can be formed without increasing the thickness of the first polarizing plate. Can be properly protected. In the first polarizing plate 21, in practice, a separator may be further laminated on the pressure-sensitive adhesive layer 33 until it is used for manufacturing a liquid crystal panel. Hereinafter, each component of the first polarizing plate will be described.

B-1. Polarizer The polarizer 31 has a thickness of 10 μm or less, preferably 3 μm to 10 μm, and more preferably 3 μm to 8 μm. By using a thin polarizer, the thickness of the first polarizing plate 21 can be prevented from becoming too thick, and the distance from the polarizer to the liquid crystal cell can be shortened. The polarizer 31 is typically composed of a resin film containing a dichroic material.

Any appropriate resin film that can be used as a polarizer can be adopted as the resin film. The resin film is typically a polyvinyl alcohol-based resin (hereinafter referred to as “PVA-based resin”) film.

Any appropriate resin may be used as the PVA-based resin forming the PVA-based resin film. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The degree of saponification of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. .. The saponification degree can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. The average degree of polymerization can be determined according to JIS K 6726-1994.

Examples of the dichroic substance contained in the resin film include iodine and organic dyes. These may be used alone or in combination of two or more. Preferably, iodine is used.

The resin film may be a single-layer resin film or a laminate of two or more layers.

Specific examples of the polarizer composed of a single-layer resin film include those obtained by subjecting a PVA-based resin film to dyeing treatment with iodine and stretching treatment (typically, uniaxial stretching). The dyeing with iodine is performed, for example, by immersing the PVA-based resin film in an iodine aqueous solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment or may be performed while dyeing. Further, it may be stretched and then dyed. If necessary, the PVA resin film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by dipping the PVA-based resin film in water and washing it with water before dyeing, it is possible to not only clean the surface of the PVA-based resin film and anti-blocking agents, but also swell the PVA-based resin film for dyeing. It is possible to prevent unevenness.

Specific examples of the polarizer obtained using the laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin. Examples thereof include a polarizer obtained by using a laminate with a PVA-based resin layer formed by coating on a base material. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer formed by coating on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying the solution. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to form the PVA-based resin layer as a polarizer; obtain. In the present embodiment, the stretching typically includes dipping the laminate in a boric acid aqueous solution and stretching. Further, the stretching may further include optionally stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in the aqueous boric acid solution. The resin base material/polarizer laminate thus obtained may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), or the resin base material is peeled from the resin base material/polarizer laminate. However, any appropriate protective layer may be laminated and used on the peeled surface depending on the purpose. The details of the method for manufacturing such a polarizer are described in, for example, JP 2012-73580 A. The entire description of the publication is incorporated herein by reference.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

B-2. Retardation Layer The retardation layer 32 has a thickness of 100 μm or more, preferably 100 μm to 200 μm, more preferably 100 μm to 150 μm, and further preferably 110 μm to 150 μm. When the thickness of the retardation layer is less than 100 μm, the retardation layer may warp when the liquid crystal panel warps in a high temperature and high humidity environment. Therefore, desired optical characteristics of the retardation layer may be impaired. When the thickness of the retardation layer is in the above range, desired optical characteristics of the retardation layer can be favorably maintained even when the liquid crystal panel is slightly warped in a high temperature and high humidity environment.

The retardation layer 32 may be any retardation layer having a thickness within the above range, and any appropriate retardation layer can be used. Typically, the retardation layer has an index ellipsoid of nx>nz>ny. The Nz coefficient of the retardation layer is preferably 0.1 to 0.9, more preferably 0.3 to 0.7, and further preferably 0.4 to 0.6.

The retardation layer can be formed of any appropriate material as long as the above characteristics can be obtained. A typical example is a stretched film of a polymer film. The resin forming the polymer film is preferably a norbornene resin or a polycarbonate resin. Details of the resin forming the polymer film are described in, for example, JP-A-2014-010291. The description is incorporated herein by reference.

The norbornene-based resin is a resin that is polymerized using a norbornene-based monomer as a polymerization unit. Examples of the norbornene-based monomer include norbornene and alkyl and/or alkylidene-substituted products thereof, such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene and 5-butyl. 2-norbornene, 5-ethylidene-2-norbornene, etc., and their polar substituents such as halogen; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc.; dimethanooctahydronaphthalene, its alkyl and/or alkylidene Substitutes and polar group substitutes such as halogen, for example, 6-methyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6- Ethyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4:5,8-dimethano-1,4. 4a,5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4:5,8-dimethano-1, 4,4a,5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octa Hydronaphthalene and the like; cyclopentadiene 3- to 4-mer, for example, 4,9:5,8-dimethano-3a,4,4a,5,8,8a,9,9a-octahydro-1H-benzoindene, 4, 11:5,10:6,9-trimethano-3a,4,4a,5,5a,6,9,9a,10,10a,11,11a-dodecahydro-1H-cyclopentaanthracene. The norbornene-based resin may be a copolymer of a norbornene-based monomer and another monomer.

Various products are commercially available as the polynorbornene. As specific examples, product names “Zonex” and “Zeonor” manufactured by Nippon Zeon Co., Ltd., product names “Arton” manufactured by JSR, product names “Topas” manufactured by TICONA, product names manufactured by Mitsui Chemicals, Inc. "APEL" is mentioned.

An aromatic polycarbonate is preferably used as the polycarbonate resin. The aromatic polycarbonate can be typically obtained by reacting a carbonate precursor with an aromatic dihydric phenol compound. Specific examples of the carbonate precursor include phosgene, bischloroformate of dihydric phenols, diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Can be mentioned. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of the aromatic dihydric phenol compound include 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane and bis(4-hydroxyphenyl). ) Methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)butane, 2, 2-bis(4-hydroxy-3,5-dipropylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl Cyclohexane etc. are mentioned. You may use these individually or in combination of 2 or more types. Preferably, 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane are Used. In particular, it is preferable to use 2,2-bis(4-hydroxyphenyl)propane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane together.

The polymeric film may include any suitable other thermoplastic resin. Other thermoplastic resins include polyolefin resin, polyvinyl chloride resin, cellulose resin, styrene resin, acrylonitrile/butadiene/styrene resin, acrylonitrile/styrene resin, polymethylmethacrylate, polyvinyl acetate, polyvinyl chloride. General-purpose plastics such as vinylidene-based resins; general-purpose engineering plastics such as polyamide-based resins, polyacetal-based resins, polycarbonate-based resins, modified polyphenylene ether-based resins, polybutylene terephthalate-based resins, polyethylene terephthalate-based resins; polyphenylene sulfide-based resins, polysulfone-based resins Examples include super engineering plastics such as polyether sulfone resin, polyether ether ketone resin, polyarylate resin, liquid crystalline resin, polyamideimide resin, polyimide resin, and polytetrafluoroethylene resin.

Any appropriate method can be adopted as a method for producing the stretched film. A typical example is a method in which a shrinkable film is attached to one side or both sides of the above polymer film and the film is heated and stretched. The shrinkable film is used for applying a shrinkage force in a direction orthogonal to the stretching direction during heating and stretching. Examples of the material used for the shrinkable film include polyester, polystyrene, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride and the like. A polypropylene film is preferably used because of its excellent shrinkage uniformity and heat resistance.

As the stretching method, any suitable stretching method may be adopted as long as it can impart a tension in the stretching direction of the polymer film and a contracting force in a direction orthogonal to the stretching direction in the film plane. .. The stretching temperature is preferably the glass transition temperature (Tg) or higher of the polymer film. This is because the retardation value of the obtained stretched film is likely to be uniform, and the film is unlikely to be crystallized (white turbidity). The stretching temperature is more preferably Tg+1° C. to Tg+30° C. of the polymer film, further preferably Tg+2° C. to Tg+20° C., particularly preferably Tg+3° C. to Tg+15° C., and most preferably Tg+5° C. to Tg+10° C. By setting the stretching temperature in such a range, uniform heating and stretching can be performed. Further, the stretching temperature is preferably constant in the width direction of the film. This is because it is possible to produce a stretched film having good optical uniformity with a small variation in retardation value.

The stretching ratio during the stretching can be set to any appropriate value. It is preferably 1.05 times to 2.00 times, more preferably 1.10 times to 1.50 times, further preferably 1.20 times to 1.40 times, particularly preferably 1.25 times to 1.30 times. Is. By setting the stretching ratio in such a range, a stretched film having less shrinkage of the film width and excellent mechanical strength can be obtained.

In another embodiment, a film obtained by stretching a polymer film containing a polycarbonate resin and a styrene resin is used. Details of such a retardation film are described in, for example, JP-A-2005-31621. The entire description of the publication is incorporated herein by reference.

B-3. Adhesive Layer The adhesive layer 33 is formed on the surface of the retardation layer 32 that is not in contact with the polarizer 31. The creep value of the pressure-sensitive adhesive layer 33 is preferably 40 μm/h or more, more preferably 50 μm/h or more, further preferably 60 μm/h or more, and particularly preferably 80 μm/h or more. The pressure-sensitive adhesive layer having a creep value within the above range has flexibility. By forming such a pressure-sensitive adhesive layer, the shrinkage stress of the polarizing plate placed in a high temperature and high humidity environment can be relaxed. Therefore, the warp of the liquid crystal panel under the high temperature and high humidity environment can be suppressed more effectively. The creep value of the pressure-sensitive adhesive layer is, for example, 200 μm/h or less.

The creep value of the pressure-sensitive adhesive layer can be measured as follows. A pressure-sensitive adhesive composition is applied to a protective layer of a polarizing plate including a protective layer and a polarizer to form a pressure-sensitive adhesive layer, to prepare a polarizing plate with a pressure-sensitive adhesive layer (test piece). The produced test piece is cut into a width of 10 mm and a length of 50 mm. Of the cut test pieces, a portion having a width of 10 mm and a length of 10 mm was attached to a stainless steel plate via an adhesive layer, and then treated in an autoclave (50° C., 5 atmospheric pressure) for 15 minutes, and then at room temperature for 1 hour. put. After standing, a 500 g load (tensile load) was applied to the end of the test piece that was not attached to the stainless steel plate at 23° C. for 1 hour, and the amount of displacement of the adhesive layer after applying the load The creep value of the pressure-sensitive adhesive layer can be measured by measuring the (deformation amount) using a laser creep tester.

The creep value of the pressure-sensitive adhesive layer can be adjusted by any appropriate method. For example, it can be adjusted by the molecular weight of the base polymer in the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, the addition amount of the crosslinking agent in the pressure-sensitive adhesive, and the like. More specifically, the creep value of the pressure-sensitive adhesive layer can be reduced by using a polymer having a high molecular weight as the base polymer and/or increasing the addition amount of the crosslinking agent. Further, the creep value of the pressure-sensitive adhesive layer can be increased by using a polymer having a low molecular weight as the base polymer and/or reducing the amount of the crosslinking agent added.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 50 μm, more preferably 10 μm to 40 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the shrinkage stress of the polarizing plate can be satisfactorily relaxed.

Any appropriate pressure-sensitive adhesive can be used as the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesive, acrylic urethane pressure-sensitive adhesive, urethane pressure-sensitive adhesive, silicone pressure-sensitive adhesive, organic-inorganic hybrid pressure-sensitive adhesive and the like. An acrylic pressure-sensitive adhesive is preferable from the viewpoint of transparency and durability.

The acrylic pressure-sensitive adhesive is, for example, an acrylic polymer using one or more kinds of (meth)acrylic acid alkyl ester as a monomer component, that is, a polymer having a structural unit derived from (meth)acrylic acid alkyl ester. Examples thereof include acrylic pressure-sensitive adhesives containing (homopolymer or copolymer) as a base polymer. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and (meth ) Isobutyl acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate , 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylic acid Undecyl, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate , (Meth)acrylic acid C1-C20 alkyl esters such as nonadecyl (meth)acrylate and eicosyl (meth)acrylate. Among them, (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used. The content ratio of the structural unit derived from (meth)acrylic acid alkyl ester is preferably 60 parts by weight or more, and more preferably 80 parts by weight or more with respect to 100 parts by weight of the base polymer.

The acrylic polymer is derived from another monomer component copolymerizable with the (meth)acrylic acid alkyl ester, if necessary, for the purpose of modifying cohesive strength, heat resistance, cross-linking property, etc. Units may be included. Examples of such a monomer component include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; maleic anhydride, and icotanic anhydride. Acid anhydride monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, (meth)acrylamide propane sulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalene Examples thereof include sulfonic acid group-containing monomers such as sulfonic acid.

In one embodiment, a hydroxyl group-containing monomer is used as the monomer component. As the hydroxyl group-containing monomer, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, ( Examples thereof include 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. When an isocyanate cross-linking agent is used as the cross-linking agent, 4-hydroxybutyl acrylate is preferable among them from the viewpoint of efficiently securing the cross-linking point with the isocyanate group. The content ratio of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1 parts by weight to 10 parts by weight, more preferably 0.5 parts by weight to 2 parts by weight, based on 100 parts by weight of the base polymer. ..

As the crosslinking agent, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a peroxide crosslinking agent, a melamine crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, a metal salt crosslinking agent. Agents, carbodiimide type crosslinking agents, oxazoline type crosslinking agents, aziridine type crosslinking agents, amine type crosslinking agents and the like. Among them, isocyanate crosslinking agents, epoxy crosslinking agents and/or peroxide crosslinking agents are preferably used. The crosslinking agents may be used alone or in combination of two or more.

Any appropriate crosslinking agent can be used as the isocyanate-based crosslinking agent. Examples of the isocyanate-based cross-linking agent include isocyanate monomers such as tolylene diisocyanate, chlorophenylene diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate and hydrogenated diphenylmethane diisocyanate; trimethylolpropane on these isocyanate monomers. Isocyanate compounds and the like obtained by adding polyols such as

Any appropriate crosslinking agent can be used as the epoxy-based crosslinking agent. As the epoxy-based crosslinking agent, for example, an epoxy-based resin having two or more epoxy groups in the molecule is used, and specifically, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane. , N,N,N′,N′-tetraglycidyl-m-xylenediamine, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether and the like. Be done.

Any appropriate crosslinking agent can be used as the peroxide-based crosslinking agent. Examples of peroxide crosslinking agents include dibenzoyl peroxide, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate. , T-butyl peroxy neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, and the like.

The amount of the cross-linking agent added is preferably 0.01 parts by weight to 5 parts by weight, more preferably 0.02 parts by weight to 3 parts by weight, and further preferably 0, relative to 100 parts by weight of the base polymer. 0.1 to 2.5 parts by weight, particularly preferably 0.4 to 1 part by weight. Within such a range, a pressure-sensitive adhesive layer having an appropriate creep value can be formed.

In one embodiment, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer may further include a silane coupling agent. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl). Epoxy group-containing silane coupling agent such as ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1, 3-dimethylbutylidene)propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, (meth)acryl group-containing silane coupling agents, isocyanate group-containing silane coupling agents, etc. Can be mentioned.

The addition amount of the silane coupling agent is preferably 0.01 part by weight to 1 part by weight, and more preferably 0.05 part by weight to 0.5 part by weight, relative to 100 parts by weight of the base polymer.

The pressure-sensitive adhesive may further include any appropriate additive, if necessary. Examples of the additives include tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, ultraviolet absorbers, light stabilizers, release modifiers, softening agents, surfactants, flame retardants. Etc.

B-4. Protective Layer As the protective layer 34, any suitable resin film is used. Examples of the material for forming the resin film include (meth)acrylic resins, cellulose resins such as diacetyl cellulose and triacetyl cellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, and polyethylene terephthalate resins. And the like, ester-based resins, polyamide-based resins, polycarbonate-based resins, copolymer resins thereof, and the like. The “(meth)acrylic resin” means an acrylic resin and/or a methacrylic resin.

In one embodiment, a (meth)acrylic resin having a glutarimide structure is used as the (meth)acrylic resin. The (meth)acrylic resin having a glutarimide structure (hereinafter, also referred to as glutarimide resin) is disclosed in, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, and JP-A-2006-328329. No. 2006-328334, No. 2006-337491, No. 2006-337492, No. 2006-337493, No. 2006-337569, No. 2007-009182, No. 2009- It is described in JP-A-161744 and JP-A-2010-284840. These descriptions are incorporated herein by reference.

The moisture permeability of the protective layer 34 is preferably 1.0 g/m ² /24 hr or less, more preferably 0.8 g/m ² /24 hr or less, and further preferably 0.6 g/m ² /24 hr or less. Yes, and particularly preferably 0.4 g/m ² /24 hr or less. When the moisture permeability of the protective layer is in such a range, it is possible to further suppress the dimensional change of the protective layer under the high temperature and high humidity environment, and as a result, further suppress the warpage of the liquid crystal panel under the high temperature and high humidity environment. obtain.

The thickness of the protective layer is typically 10 μm to 100 μm, preferably 20 μm to 40 μm. The protective layer is typically laminated on the polarizer via an adhesive layer (specifically, an adhesive layer or a pressure-sensitive adhesive layer). The adhesive layer is typically formed of a PVA-based adhesive or an activated energy ray-curable adhesive. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. This acrylic pressure-sensitive adhesive may be the same as or different from the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer.

C. Second Polarizing Plate The second polarizing plate 22 has a thickness of 150 μm or less, preferably 80 μm to 140 μm, and more preferably 110 μm to 130 μm. The second polarizing plate 22 is a polarizing plate having a thickness smaller than that of the first polarizing plate 21. The second polarizing plate may have a thickness of 150 μm or less, and includes any appropriate constituent element. The second polarizing plate 22 typically has a polarizer 35, an adhesive layer 36, and a protective layer 37. The second polarizing plate 22 is attached to the liquid crystal cell via the adhesive layer 36. Practically, a separator may be further laminated on the pressure-sensitive adhesive layer 36 until it is used for manufacturing a liquid crystal panel.

C-1. Polarizer Any appropriate polarizer can be used as the polarizer of the second polarizing plate. The thin polarizer (for example, having a thickness of 10 μm or less) disclosed in the section of the first polarizing plate may be used, or a thick polarizer may be used. When a thick polarizer is used, the thickness of the polarizer is, for example, 10 μm to 35 μm, preferably 15 μm to 30 μm.

C-2. Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer can be formed using any appropriate pressure-sensitive adhesive. The pressure-sensitive adhesive layer may be formed by using the pressure-sensitive adhesive (pressure-sensitive adhesive having a high creep value) used in the formation of the first polarizing plate, and other pressure-sensitive adhesives (for example, pressure-sensitive adhesive having a low creep value) may be used. It may be formed by using. By forming the pressure-sensitive adhesive layer of the second polarizing plate also using the pressure-sensitive adhesive used in the first polarizing plate, the shrinkage stress of the liquid crystal panel as a whole is relaxed, and the warp of the liquid crystal panel in a higher temperature and high humidity environment is prevented. Can be suppressed.

C-3. Protective Layer The protective layer can be formed of any suitable film. For example, the film used for the protective layer of the first polarizing plate can be used.

D. Liquid Crystal Panel A liquid crystal panel of the present invention includes the above-mentioned set of polarizing plates and a liquid crystal cell. Typically, the first polarizing plate is laminated on one surface of the liquid crystal cell via the pressure-sensitive adhesive layer, and the second polarizing plate is laminated on the other surface of the liquid crystal cell. In one embodiment, the first polarizing plate may be arranged on the back side and the second polarizing plate may be arranged on the viewing side.

Any appropriate drive mode can be adopted as the drive mode of the liquid crystal cell. As a specific example of the drive mode, an STN (Super Twisted Nematic) mode, a TN (Twisted Nematic) mode, an IPS (In-Plane Switching) mode, a VA (Vertical Aligned Edge) mode, and an OCB (Optically Horizontal Aligned) mode. Aligned Nematic mode, ASM (Axially Symmetric Aligned Microcell) mode, ECB (Electrically Controlled Birefringence) mode, etc. are mentioned. In one embodiment, an IPS mode liquid crystal cell is preferably used.

The thickness of the liquid crystal cell can be set to any appropriate value. For example, it is 0.7 mm or less, preferably 0.5 mm or less, and more preferably 0.5 mm to 0.2 mm.

E. Liquid Crystal Display Device The liquid crystal panel of the present invention can be applied to an image display device. In one embodiment, the liquid crystal panel may be arranged so that the first polarizing plate is on the back side and the second polarizing plate is on the viewing side. When the second polarizing plate further includes the antireflection layer, the antireflection layer may be disposed on the viewing side of the image display device so that the antireflection layer is on the viewing side. As described above, a thick retardation layer is used in the polarizing plate set of the present invention. Therefore, it can be suitably used for a large-sized image display device.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The measuring method of each characteristic is as follows.

(1) Creep value of pressure-sensitive adhesive layer The pressure-sensitive adhesive layer was formed by coating each of the pressure-sensitive adhesives A to C on the protective layer of the polarizing plate obtained in Production Example 1 so as to have a thickness of 20 μm. A plate was made. The produced polarizing plate was cut into a piece having a width of 10 mm and a length of 50 mm to obtain a measurement sample. The end portion (width 10 mm x length 10 mm) of the cut measurement sample was attached to a stainless steel plate via an adhesive layer, and after autoclaving at 50°C for 5 minutes at 15 atm for 1 hour at room temperature. The amount of displacement (deformation) of the pressure-sensitive adhesive layer was measured when a load of 500 g (tensile load) was applied to the end opposite to the end attached to the stainless steel plate at 23° C. for 1 hour, This was taken as the creep value of the pressure-sensitive adhesive layer (laser creep tester).

(2) Retardation variation The in-plane retardation variation of the retardation layers used in the first polarizing plates of Examples 1 to 4 and Comparative Examples 1 to 2 was measured by a retardation measuring device (manufactured by Oji Scientific Instruments Co., Ltd., product Name: KOBRA-WPR).
The in-plane retardation variation of the retardation layer was evaluated according to the following criteria.
◯: 4 nm or less △: 4 nm or more and 7 nm or less x: 7 nm or more

(3) Axial variation The in-plane axial variation of the retardation layers used in the first polarizing plates of Examples 1 to 4 and Comparative Examples 1 and 2 was measured by a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., product name: KOBRA-WPR).
The in-plane axial variation of the retardation layer was evaluated according to the following criteria.
◯: 0.5° or less △: 0.5° or more and 0.7° or less x: 0.7° or more

<Synthesis Example 1> Synthesis of adhesive A In a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer, 100 parts of butyl acrylate, 5 parts of acrylic acid, 0.075 parts of 2-hydroxyethyl acrylate. And 2,2'-azobisisobutyronitrile (0.3 parts) were added together with ethyl acetate to prepare a solution. Then, the solution was stirred while blowing nitrogen gas, and reacted at 60° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Further, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution (A1) in which the solid content concentration was adjusted to 30%.
A cross-linking agent containing 0.6 part of a compound having an isocyanate group as a main component, as a cross-linking agent, based on 100 parts of the solid content of the obtained acrylic polymer solution (A1) (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KMB-403") as a silane coupling agent are compounded in this order. To prepare adhesive A.

<Synthesis Example 2> Synthesis of Adhesive B In a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer, 99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate and 2,2'. -Azobisisobutyronitrile (0.3 parts) was added together with ethyl acetate, and the mixture was reacted under a nitrogen gas stream at 60°C for 4 hours. Next, ethyl acetate was added to the reaction solution to obtain a solution (solid content concentration 30%) containing an acrylic polymer having a weight average molecular weight of 1,650,000.
0.15 parts of dibenzoyl peroxide (manufactured by NOF CORPORATION, trade name: Nyper BO-Y) and 0.08 parts of trimethylolpropane xylene diisocyanate per 100 parts of solid content of the obtained acrylic polymer solution. (Mitsui Takeda Chemical Co., Ltd., trade name: Takenate D110N) and 0.2 parts of silane coupling agent (Soken Chemical Co., Ltd., trade name: A-100, acetoacetyl group-containing silane coupling agent) acryl. The adhesive B was prepared by adding it to the base polymer solution.

<Synthesis Example 3> Synthesis of pressure-sensitive adhesive composition C A reaction vessel equipped with a cooling tube, a nitrogen introducing tube, a thermometer and a stirrer was charged with 81.9 parts of butyl acrylate, 13 parts of benzyl acrylate, 5 parts of acrylic acid, 4- 0.1 parts of hydroxybutyl acrylate and 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with 100 parts of ethyl acetate, and nitrogen gas was introduced while gently stirring to replace nitrogen. Then, the temperature of the liquid in the flask was kept at around 55° C. to carry out a polymerization reaction for 8 hours to prepare an acrylic polymer solution.
0.45 part of an isocyanate cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L, an adduct of tolylene diisocyanate of trimethylolpropane), relative to 100 parts of the solid content of the obtained acrylic polymer solution, 0 1 part of benzoylperoxyside (NOF Corporation, trade name: Niper BMT) and 0.1 part of a silane coupling agent (produced by Shin-Etsu Chemical Co., Ltd., trade name: KBM403) are acrylic polymers. Adhesive C was prepared by adding to the solution.

<Production Example 1> Production of Polarizer Laminate 1 As a resin substrate, an elongated isophthalic acid-copolymerized polyethylene terephthalate (IPA copolymerized PET) film having a long shape, a water absorption of 0.75% and a Tg of 75°C ( Thickness: 100 μm) was used. One side of the base material is subjected to corona treatment, and polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6) are applied to the corona-treated surface. %, saponification degree 99.0 mol% or more, Nippon Gohsei Kagaku Kogyo Co., Ltd., trade name “Gosephimmer Z200”) at a ratio of 9:1 was applied and dried at 25° C. to a thickness of 11 μm. A PVA-based resin layer was formed to produce a laminate.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120° C. (in-air auxiliary stretching).
Next, the laminated body was immersed in an insolubilizing bath having a liquid temperature of 30° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Then, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and 1.5 parts by weight of potassium iodide was added, and the resultant was immersed for 60 seconds in an aqueous iodine solution (dyeing treatment). ..
Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30° C. (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water). (Crosslinking treatment).
Then, the laminate was immersed in an aqueous boric acid solution having a liquid temperature of 70° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water). Meanwhile, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (underwater stretching).
After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
Then, on the surface of the PVA-based resin layer (polarizer) of the laminate, a PVA-based resin aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “Gosephimmer (registered trademark) Z-200”, resin concentration: 3% by weight) ) Is applied, and a methacrylic resin film (thickness: 25 μm, a film containing a (meth)acrylic resin having a glutarimide structure) that constitutes the protective layer is laminated and heated in an oven maintained at 60° C. for 5 minutes. did. Then, the resin base material was peeled from the PVA-based resin layer. Thus, a polarizer laminate (a polarizing plate having a structure of protective layer/polarizer) was obtained. The thickness of the polarizer was 5 μm, and the single transmittance was 42.3%.

<Production Example 2> Production of Polarizer Laminate 2 A polyvinyl alcohol (average polymerization degree: 2400, saponification degree: 99.9 mol%) film having a thickness of 60 µm was immersed in warm water at 30°C for 60 seconds to be swollen. Next, it was immersed in an iodine/potassium iodide aqueous solution (weight ratio: 0.5/8, concentration: 0.3% by weight), and dyed while stretching the film up to 3.5 times. Then, it was stretched in a boric acid ester aqueous solution at 65° C. so that the total stretching ratio was 6 times. After stretching, it was dried in an oven at 40° C. for 3 minutes to obtain a polarizer.
Then, a first transparent protective film (TAC film, thickness 40 μm) and a second transparent protective film (acrylic resin film, thickness: 30 μm) are attached to both sides of the above-mentioned polarizer through an adhesive layer and then polarized. It was a child laminate. The thickness of the polarizer was 22 μm, and the single transmittance was 41.5%.

<Production Example 3> Preparation of retardation layer 1 A polymer film containing a resin obtained by hydrogenating a ring-opening polymer of a norbornene-based monomer having a thickness of 130 μm (manufactured by JSR Corporation, trade name “ARTON FLZU130D0”, contracted on both sides. Film (C) (manufactured by Toray Industries, Inc., product name: Trefan) was attached via an acrylic pressure-sensitive adhesive layer (thickness: 15 μm), and then held in the longitudinal direction of the film by a roll stretching machine. The film was stretched 1.42 times in an air-circulating constant-temperature oven at 146° C.±1° C. The thickness of the obtained retardation film was 138 μm, Re(550)=270 nm, and Nz=0.5. This retardation film was used as retardation layer 1.

<Production Example 4> Preparation of retardation layer 2 10 kg of polyarylate was dissolved in 73 kg of toluene to prepare a coating liquid. After that, the coating liquid is directly applied onto a shrinkable film (longitudinal uniaxially stretched polypropylene film, manufactured by Tokyo Ink Co., Ltd., trade name “Nobren”), and the coating film is dried at a temperature of 60° C. for 5 minutes. And dried at 80° C. for 5 minutes to form a shrinkable film/birefringent layer laminate. The obtained laminate is stretched at a stretching temperature of 155° C. at a stretching temperature of 155° C. in the MD direction by a shrinkage ratio of 0.70 times and in the TD direction by a stretch ratio of 1.15 times to obtain a retardation film on the shrinkable film. Formed. Then, the retardation film was peeled from the shrinkable film. The thickness of the retardation film was 17.0 μm, Re(550)=300 nm, and Nz=0.5. This retardation film was used as retardation layer 2.

[Example 1]
An acrylic pressure-sensitive adhesive was applied to the polarizer of the polarizer laminate obtained in Production Example 1 so as to have a thickness of 20 μm, and the retardation layer 1 was laminated. Next, the pressure-sensitive adhesive B was applied to the surface of the laminated retardation layer 1 which was not in contact with the polarizer so as to have a thickness of 20 μm to form a pressure-sensitive adhesive layer, and a first polarizing plate was obtained.
Separately, a pressure-sensitive adhesive A was applied to the polarizer of the polarizer laminate obtained in Production Example 1 so as to have a thickness of 23 μm to form a pressure-sensitive adhesive layer, and a second polarizing plate was obtained.
Each evaluation was performed using the obtained set of the first polarizing plate and the second polarizing plate.

[Example 2]
A first polarizing plate was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive A was used instead of the pressure-sensitive adhesive B to form the pressure-sensitive adhesive layer (thickness: 23 μm).
The pressure-sensitive adhesive A was applied to the polarizer of the polarizer laminate obtained in Production Example 2 to have a thickness of 20 μm to form a pressure-sensitive adhesive layer, and a second polarizing plate was obtained.
Each evaluation was performed using the obtained set of the first polarizing plate and the second polarizing plate.

[Example 3]
A second polarizing plate was obtained in the same manner as in Example 2 except that the pressure sensitive adhesive layer of the second polarizing plate was changed to the pressure sensitive adhesive A to form the pressure sensitive adhesive B.
A polarizing plate set was obtained in the same manner as in Example 2 except that the obtained second polarizing plate was used. Each evaluation was performed using this set.

[Example 4]
A second polarizing plate was obtained in the same manner as in Example 2 except that the pressure sensitive adhesive layer of the second polarizing plate was replaced with the pressure sensitive adhesive layer A and the pressure sensitive adhesive C was used.
A polarizing plate set was obtained in the same manner as in Example 2 except that the obtained second polarizing plate was used. Each evaluation was performed using this set.

(Comparative Example 1)
A polarizing plate set was obtained in the same manner as in Example 1 except that the retardation layer 2 was used instead of the retardation layer 1. Each evaluation was performed using this set.

(Comparative example 2)
A first polarizing plate was obtained in the same manner as in Example 1 except that the polarizer laminate obtained in Production Example 2 was used.
A second polarizing plate was obtained in the same manner as in Example 1 except that the polarizer laminate obtained in Production Example 2 was used.
Each evaluation was performed using the obtained set of the first polarizing plate and the second polarizing plate.

<Evaluation>
The polarizing plate sets of Examples 1 to 4 and Comparative Examples 1 and 2 were bonded together with an adhesive layer sandwiching a glass plate (thickness: 0.55 mm) to obtain a laminate. The following evaluation was performed using the obtained laminated body. The results are shown in Table 1.
1. Appearance unevenness and light leakage The obtained laminate was placed on a backlight, and the presence or absence of unevenness in the four corners and light leakage was confirmed and evaluated according to the following criteria.
◎: No unevenness in the four corners and light leakage ◯: There is unevenness in the four corners or light leakage ×: There is unevenness in the four corners and light leakage

2. Amount of Warp The focal lengths of the four corners of the second polarizing plate (viewing side polarizing plate) of the obtained laminate were measured using a flat biaxial measuring device (manufactured by Mitutoyo Corporation, product name: Quick Vision Apex). Next, the laminate was placed under reliability test conditions (85° C.) for 24 hours, and the focal lengths at the four corners of the second polarizing plate side (viewing side polarizing plate) were measured in the same manner. The difference between the focal lengths before and after the reliability test was applied to each corner was calculated, and the average value of the four corners was used as the amount of warpage of each polarizing plate set. The amount of each warp was evaluated according to the following criteria. In Table 1, "+" indicates that the laminate curls downward (that is, on the back side), and "-" indicates that the laminate protrudes upward (that is, the viewing side). It shows that each is curled.
◎: 0 mm or more and 0.5 mm or less ◯: Over 0.5 mm and 1.0 mm or less Δ: Over 1.0 mm and 2.0 mm or less ×: Over 2.0 mm

As is clear from Table 1, the sets of the polarizing plates of Examples 1 to 4 had suppressed warpage even when placed in a high temperature and high humidity environment of the laminate. With these polarizing plate sets, unevenness in appearance and light leakage were also small. In addition, the optical properties of the retardation layer were maintained well.

The polarizing plate set of the present invention is suitably used for a liquid crystal display device.

10 Liquid Crystal Cell 21 First Polarizing Plate 22 Second Polarizing Plate 31 Polarizer (First Polarizer)
32 Retardation Layer 33 Adhesive Layer 34 Protective Layer 35 Polarizer (Second Polarizer)
36 Adhesive Layer 37 Protective Layer 100 Liquid Crystal Panel

Claims (7)

A first polarizing plate having a thickness of 200 μm or more and 300 μm or less arranged on one surface of the liquid crystal cell, and a second polarizing plate having a thickness of 150 μm or less arranged on the other surface of the liquid crystal cell. A set of polarizing plates,
The first polarizing plate has a retardation layer having a thickness of 100 μm or more, a polarizer having a thickness of 10 μm or less disposed on one surface of the retardation layer, and a pressure-sensitive adhesive disposed on the other surface of the retardation layer. With layers,
A set of polarizing plates, wherein the first polarizing plate is laminated on a liquid crystal cell via the adhesive layer. The first polarizing plate further has a protective layer,
The set of polarizing plates according to claim 1, wherein the protective layer is laminated only on one surface of the polarizer. The set of polarizing plates according to claim 1 or 2, wherein the adhesive layer has a creep value of 80 µm/h or more. The set of polarizing plates according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 10 μm to 40 μm. The set of polarizing plates according to claim 1, wherein the first polarizing plate is arranged on the back side and the second polarizing plate is arranged on the viewing side. A liquid crystal panel comprising the set of polarizing plates according to claim 1 and a liquid crystal cell. The liquid crystal panel according to claim 6, wherein the distance between the liquid crystal cell and the polarizer of the first polarizing plate is 160 μm to 190 μm.

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